Does the ship stay in the same time zone for the duration of the cruise regardless of the time where they land? For instance, my cruise we're leaving from Miami and going to Montego Bay. Miami is EST. I believe Jamaica is too, but they don't do daylight savings time so right now they're an hour behind. Will the ship keep on Miami time or go to Jamaica time and then change to Cartagena time and so on?
The ship time, is its time. Wherever you are, be sure to set your watches to the ship time. They will port and debark via the ship's time. They announce time changes in the papers, on tv, and usually make two or three announcements.
Sometimes cruises will stay on the same time as their homeport, sometimes not. It is really up to the Captain. I've been on western Caribbean cruises where we stayed on Miami time the whole way, but there have also been a couple where we did time changes. There really is no way to tell until you board. Even if someone says they just did the same cruise as yours and they did X, you could be doing Y when your cruise starts.
Normally, and almost always without exception the ship will stay on the time of the embarkation port for Caribbean cruises from Miami. This can get tricky for some ports that don't observe Daylight Savings Time. Especially if you are booking a private excursion. You can always check with the guest service desk to make sure.
Most of the Caribbean cruises I've been on lately have adhered to local time, not the time at the embarkation point. The cruise information sheet you get every night will tell you whether you need to set your clocks/watches ahead or behind for the next port. They usually suggest you do it before retiring for the night on the night before you arrive at a port.
I remember doing the time changes on HAL and Celebrity, but not on Carnival. I think we stayed on Miami time while on the Freedom and Liberty Of The Seas, but we haven't been on Miami cruises since 2007.
On the Grandeur in June we did change to Atlantic Standard Time (plus one hour) on the second evening and remained on it for 5 days.
On our Princess cruise in December/January, we changed time 4 times. On some of our cruises, we've never changed. I remember one cruise leaving St. Thomas, ship's time was 6pm, it was as dark as if it were midnight. Can't remember what island time was, but it sure was different than the ship's time.
I was curious about this because I know sometimes we changed time, but other times I couldn't remember doing it. So I checked my Princess Patters from all my Mexican Riviera cruises and sure enough: sometimes we did and sometimes we didn't. Dave has it exactly right:
"Even if someone says they just did the same cruise as yours and they did X, you could be doing Y when your cruise starts."
The best thing I can tell you is pay attention to announcements. I'm not sure if the cruise compass is someplace they will post the time the ship will follow when it is in port, or if you have to listen for announcements or tune to the Royal Caribbean channel on your TV.
2007 - Majesty of the Seas
2009 - Enchantment of the Seas
2010 - Freedom of the Seas